introduce HTTParty-configuration, fix #61

This commit introduces a new option attribute, namely `httparty`, that allows passing configuration down to HTTParty.
For instance to disable verification of self-signed certificates you can now do as follow:

    client1 = Gitlab.client(endpoint: 'https://api1.example.com', private_token: 'user-001', httparty: {verify: false})

The list of HTTParty configuration attributes can be found at https://github.com/jnunemaker/httparty
Add support for annotated tag creation. Update tests for create_tag.
Merge pull request #67 from barraq/master

introduce HTTParty-configuration, fix #61
Update tests for create_tags method so it more closely matches what will happen in Gitlab 7.5.0.
Support pagination in Gitlab.merge_request_comments
Merge pull request #74 from nthx/master

Support pagination in Gitlab.merge_request_comments
Merge pull request #81 from asedge/annotated_tags

Add support for annotated tag creation. Update tests for create_tag.
Add labels api for list, create, edit and delete.
Merge pull request #72 from artworx/master

Add labels api for list, create, edit and delete.
Adds support for comments on commits
Merge pull request #88 from jeroenj/commit-comments

Adds support for comments on commits